Electronic structure of triple-decker sandwich complexes with P6 middle rings. Synthesis and x-ray structure determination of bis(.eta.5-1,3-di-tert-butylcyclopentadienyl)(.mu.-.eta.6:.eta.6-hexaphosphorin)diniobium

Abstract

The cothermolysis of [Cp"Nb(CO),] (11, Cp" = C6H3(tBu)2-1,3, and P4 affords the 26-valence-electron triple-decker sandwich complex [ (CpWb)2Gc-q6:q6-Ps)l (2). Ita X-ray structure determination shows that the Po middle deck is severely bisallylically distorted (orange crystals, monoclinic space group R1/n, a IntroductionDuring the last six years many novel triple-decker sandwich complexes with cyclo-P,-or cyclo-As,-unita as middle deck have been ~yntheaized."~ Several theoretical studies gave some insight into the bonding and electronic structure of these compound^.^^^

Direct insertion of sulfur, selenium and tellurium atoms into metallaborane cages using chalcogen powders

“…Alternatively, as the available cluster bonding electrons of 6 are insufficient to meet the requirements of single eight-vertex nido-geometry, it could be better described as 26 valence electron (ve) triple-decker complex [47][48][49][50]. In addition, 6 is isoelectronic to those of arene-bridged-[(g 5 -C 5 H 5 V) 2 (l-g 6 :g 6 -C 6 H 6 )] [51], triple-decker sandwich complexes, for example, [(g 5 -C 5 Me 4 EtV) 2 (l-g 6 :g 6 -P 6 )] [52] and [(g 5 -C 5 H 3 t Bu 2 Nb) 2 (l-g 6 :g 6 -P 6 )] [53], and closo-[(g 5 -C 5 Me 5 W) 2 B 6 H 10 ] [54]. The distance between two selenium atoms (Se1 and Se2 in Fig.…”

Early-Transition-Metal-Mediated Activation and Transformation of White Phosphorus

“…54,[62][63][64][65] Several of the P 6 triple-decker complexes adopt the expected D 6h configuration with a planar P 6 unit, but in the case of 49 a distortion to a chair-like cyclo-hexaphosphido form occurs, and the P 6 ligand binds in a µ 2 :η 3 ,η 3 fashion as a P 6 -6 ligand. Several different geometries can be obtained for P 6 ligands as illustrated by the activation of P 4…”

Niobium and Tantalum

“…513 ' 517 The THF molecules in [Li 2 (THF) 2 Cp*TaS 3 ] 2 are displaced by DME or TMEDA to form Li 2 (DME)Cp*TaS 3 and Li 2 (TMEDA) 2 Cp*TaS 3 , respectively; however, when Cp*TaCl 4 reacts with four to five equivalents of Li 2 S 2 in the presence of TMEDA, LiCl is retained and [Li 3 (TMEDA) 2 Cp*TaS 3 Cl] 2 (u-TMEDA) is isolated. 513 Similarly, reacting Cp*TaCl 4 with four to five equivalents of Li 2 Se 2 in THF affords yellow crystals of Cp*TaSe 3 Li 3 Cl(THF) 3 (48). 518 When Cp*TaCl 4 reacts with Li 2 Se in THF, followed by treatment with TMEDA, the final "LiCl" unit was removed and yellow crystals of Cp*TaSe 3 Li 2 (TMEDA) 2 are isolated in high yield.…”